Adolescents and young adults 24 years of age and under are among the fastest growing U.S. demographic groups acquiring HIV. One-half of new infections occur in individuals <25 years of age, and 25% below the age of 21. Sexual minority stress, personal attributes (e.g. perceived vulnerability, self-control, self-efficacy, communication skills), psychosocial well-being (e.g. psychological distress, loneliness, social support, family cohesion, self-esteem), and substance use have all been hypothesized as factors associated with HIV risk behaviors in vulnerable youth. Few studies have explored these complex interactions in specific subpopulations of youth at greatest risk of exposure to HIV. This proposed cross-sectional pilot project, consistent with the conceptual goals of NIMH program announcements (PAS-00-136: Demographic Research on Sexual Behaviors Related to HIV, and PA-01-096: Behavioral, Social, Mental Health, and Substance Abuse Research With Diverse Populations) will pilot test the utility of a conceptually grounded theoretical model of HIV-risk that emphasizes the interplay of interpersonal, psychological, and cognitive factors. Study aims are: (1) to examine the relation among personal and social constructs and the engagement of HIV-related risk behaviors, and (2) to identify the most important factors associated with HIV-related risk in a specific subpopulation of vulnerable youth. We will recruit 250 ethnically diverse youth between the ages of 16-24 (inclusive) seeking services at community-based medical and/or social service agencies in Chicago. Youth will participate in interviews and will complete questionnaires to assess key constructs in our conceptual model. We will use multiple methods in this pilot project to test the associations in the theoretical model and to identify factors associated with vulnerable youth at risk of acquiring HIV. The long-term significance of this research is to guide the development of a large-scale investigation of the promising risk mechanisms identified here with a more diverse sample and to assist in the development of a theoretically based HIV prevention intervention specific to our population. Our findings will assist in the creation of much needed HIV prevention programming for vulnerable youth. This study is part of an overall program of research to develop HIV prevention interventions that target the unique social and personal needs of this subpopulation of youth. [unreadable] [unreadable]